<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .a {
            width: 1000px;
            height: 100px;
            background-color: #f0f;
            /* a是没有浮动的 */
        }

        .a1 {
            width: 100px;
            height: 100px;
            background-color: #f00;
            float: left;
        }

        .a2 {
            width: 100px;
            height: 100px;
            background-color: #f00;
            float: right;
        }

        .b {
            width: 1000px;
            height: 58px;
            background-color: #000;
        }

        .c {
            width: 1000px;
            height: 500px;
            background-color: #666;
        }

        .c1 {
            width: 500px;
            height: 500px;
            background-color: #0f0;
            float: left;
        }

        .c2 {
            width: 300px;
            height: 500px;
            background-color: #0ff;
            float: left;
        }

        .c3 {
            width: 200px;
            height: 500px;
            background-color: blueviolet;
            float: left;
        }
    </style>
</head>

<body>

    <!-- 

        画页面是上下分，再左右分
        
     -->


    <!-- a开始  -->
    <div class="a">
        <div class="a1"></div>
        <div class="a2"></div>
    </div>
    <!-- a结束 -->

    <div class="b"></div>

    <!-- c start  -->
    <div class="c">
        <div class="c1"></div>
        <div class="c2"></div>
        <div class="c3"></div>

    </div>
    <!-- c end  -->

</body>

</html>